An annular combustion chamber of a turbomachine comprises, at its upstream end a rigid, annular chamber-bottom wall and comprises at its downstream end flanges for attachment to inner and outer casings. An annular upstream fairing is attached to the chamber bottom and makes it possible to direct the airflow coming into or around the combustion chamber. The chamber bottom wall and the fairing comprise openings for the entry of air into the chamber, and for the insertion of fuel injectors. The inner and outer attachment flanges, at the downstream end of the chamber, have holes in them in order to allow the passage of the air traveling around the combustion chamber and therefore have a certain flexibility.
Such a combustion chamber has a certain number of disadvantages because of its method of attachment.
Specifically, its single downstream attachment leads to a mounting of the chamber in an overhanging manner. The vibrations generated during the operation of the turbomachine cause the upstream portion of the chamber to vibrate which leads to a misalignment between the injectors and the chamber and does not allow the production of an ideal combustion of the injected fuel. These vibrations also contribute to limiting the service life of the chamber.
It would therefore be worthwhile for the attachment flanges to be sufficiently rigid to limit the vibrations of the chamber. However, during the operation of the turbomachine, the pressure variations between the inter-casing enclosure and the outside of this enclosure and the temperature variations induce relative movements of the inner and outer casings and of the chamber walls, which requires making the downstream flanges flexible.
In certain configurations, in which the characteristics of the materials of the casings and of the chamber walls are very different, or else when the geometry of the flanges is complex, the flanges require a flexibility that is incompatible with their mechanical and aerodynamic design, necessary to comply with the vibration limits of the chamber.